ISB Exam 1: Ch 3
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65 terms
Terms | Definitions |
|---|---|
 What was discovered in Monteverde, Costa Rica in 1964? | Golden Toads |
| Species | A population or group of populations, whose members share common characteristics. They can breed with one another and produce fertile offspring |
| Population | A group of individuals of a species that live in the same area |
| Evolution | Means change over time |
| Biological Evolution | Genetic change in populations over time. Genetic change leads to changes in appearance, functioning or behavior over generations |
| Natural Selection | Traits that enhance survival and reproduction. These traits are past on more frequently to future generations that those traits that do not aid in survival and reproduction. |
| What must we understand in order to appreciate environmental science? | Natural Selection |
| What did Charles Darwin and Alfred Wallace propose in 1858? | They proposed natural selection as the mechanism of evolution |
| Adaptation | The process where, over time, characteristics that lead to better reproductive success will evolve in the population |
| Adaptive Trait | A trai that promotes reproductive success |
| Mutations | Accidental changes in DNA that may be passed on to future generations. |
| What also leads to genetic variation? | Sexual Reproduction |
| Natural Selection changes characteristics through: | -Directional Selection, which drives a feature in one direction. - Stabilizing Selection, which favors intermediate traits. - Disruptive Selection, which traits diverge in two or more directions. |
| Convergent Evolution | Unrelated species may evolve similar traits because they live in similar environments. |
| Artificial Selection | The process of selection conducted under human direction |
| Biological Diversity (Biodiversity) | The variety of life across all levels of biological organization: - species - genes - populations - communities |
| Speciation | The process of generating new species |
| Allopatric Speciation | Species formation due to physical separation of populations. This is the main mode of speciation. |
| Sympatric Speciation | Species form populations that become reproductively isolated within the same area. Examples: - Feed in different areas - Mate in different seasons - Hybridization between two species - Mutations |
| Phylogenetic Trees (cladograms) | Show relationships among species, groups, and genes. Scientists can trace how certain traits evolved. |
| Fossil | An imprint in stone of a dead organism |
| Fossil Record | The cumulative body of fossils worldwide |
| Extinction | The disappearance of species from Earth. Species last 1 to 10 million years. |
| Equation to find the number of species | Speciation minus extinction |
| Extinction is a natural process, BUT... | ...humans profoundly affect rates of extinction and biodiversity loss affects people directly. |
| When does extinction occur? | When the environment changes rapidly and Natural Selection cannot keep up. |
| Name a few more causes of Extinction | - Severe weather, climate change, changing in sea levels - New species, small populations - Specialized species |
| Endemic Species | A species only exists in a certain, specialized area. |
| Background Extinction Rate | Extinction usually occurs one species at a time. |
| Mass Extinction Events | Killed off massive numbers of species at once. |
| Cretaceous - Tertiary Event | Dinosaurs went extinct 65 Million years ago |
| End-Permian Event | 75-95% of all species went extinct 250 million years ago |
| How are we causing the 6th mass extinction event? | - Resource depletion, population growth, development - Destruction of natural habitats |
| Biosphere | The total living things on Earth and the areas they inhabit. |
| Community | Interacting species living in the same area |
| Ecosystem | Communities and the nonliving material and the forces they interact with. |
| Population Ecology | Investigates the dynamics of population change and the factors affecting the distribution and abundance of members of a population and why some populations increase and others decrease. |
| Ecosystem Ecology | Studies living and nonliving components of systems to reveal patterns and to see how nutrient and energy flows. |
| Habitat | the environment where an organism lives, including living and nonliving things. |
| Habitat Use | Each organism thrives in certain habitats, but not others. |
| Habitat Selection | The process by which organisms actively select habitats in which to live |
| Niche | An organism's use of resources. This term can also refer to the organism's functional role in a community, it's habitat use, food selection, role in energy and nutrient flow, and interactions with other individuals. |
| Specialists | Have narrow niches and specific needs. Extremely good at what they do, but vulnerable when conditions change. |
| Generalists | Species with broad niches. They use a wide array of habitats and resources and can live in many different places. |
| Population Size | The number of individual organisms present at a given time. |
| Population Density | Number of individuals in a population per unit area. There are "low" and "high" densities |
| Low Densities | For large organisms, who need many resources and a large area to survive. It is more difficult to find a mate with less organisms due to lack of space which is caused my the size of the organisms. |
| High Densities | Easier to find mates, but there is an increase in competition and vulnerability to predation. There is also an increased transmission of diseases. |
| Population Distribution (dispersion) | Special arrangement of organisms: - Random Distribution - Uniform Distribution - Clumped Distribution |
| Random Distribution | Haphazardly located individuals and there is no pattern. |
| Uniform Distribution | Individuals evenly spaced. This distribution includes territoriality and competition. |
| Clumped Distribution | Arranged according to availability of resources. This distribution is the most common in nature. |
| Sex Ratio | proportion of males to females |
| Age Distribution (structure) | the relative numbers of organisms of each age in a population. Displayed in an "Age Structure diagram" (pyramid). |
| Survivorship Curves | the likelihood of death varies with age Type I: more deaths at older ages Type II: Equal number of deaths at all ages Type III:more deaths at younger ages |
| Natality | Births within the population |
| Mortality | Deaths within the population |
| Immigration | Arrival of individuals outside of the population. Adds to number of individuals |
| Emigration | Departure of individuals from the population. Subtracts from number of individuals. |
| Crude birth (death) rates | number of births (deaths) per 1000 individuals per year |
| Natural Rate of populations growth | (crude birth rate) - (crude death rate) |
| Population Growth Rate | (crude birth rate + immigration rate) - (crude death rate + emigration rate) |
| Exponential Growth | A populations increases by a fixed percent. Graph has a J-curve. It occurs in nature due to small population, low competition, and ideal conditions. |
| Limiting Factors | physical, chemical and biological attributes of the environment. They restrain population growth. |
| Environmental resistance | all limiting factors taken together. - stabilizes the population size - space, food, water, mates, shelter |
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